The present invention relates to an apparatus for manufacturing insulation material from a phenol-formaldehyde resin such as is disclosed in co-pending U.S. application Ser. No. 167,763, filed July 14, 1980, and assigned to the same assignee as the present application.
Insulation board has previously been made from a variety of compositions such as polyurethane, polystyrene and the like. Such compositions, while providing a useful insulation, have several inherent drawbacks in terms of their applications and methods of manufacture. For example, polyurethane has been criticized as a hazard due to the toxic fumes that result when the material is ignited. Also, in the formation of polyurethane and polystyrene foam boards, either a discontinuous process must be employed to obtain a suitable, stable product or the speed of the manufacturing process must be unacceptably slow in order to control the foaming of the composition to assure production of a product that will have sufficient insulating properties. As noted in the above-identified U.S. application, Ser. No. 167,763, the use of a phenol-formaldehyde resin as a foaming composition avoids a number of the problems of the prior art foaming compositions. However, one of the drawbacks in the prior art that has prevented the widespread use of a phenol-formaldehyde resin is the lack of structural integrity in the resulting product. While to a large extent, these problems have been overcome by use of the composition of the above-identified Ser. No. 167,763, it has been found that a superior product can be obtained, that is, one having adequate flexibility without crumbling yet improved structural integrity and strength by use of the improved foaming apparatus of the present invention.
In summary, it has been found that where the phenol-formaldehyde resin composition of co-pending application, Ser. No. 167,763, is allowed to freely expand in a large volume chamber to fill the chamber and then continue to foam in a steady state condition under back pressure developed by the process, an insulation board is obtained that is somewhat flexible as compared to prior phenolic foams but which is significantly less friable and thus usable in a substantially greater number of insulation applications than has previously been the case. However, to further broaden the number of structural applications to which the phenol-formaldehyde compositions of the previously identified application may be put, it is desirable to obtain a stronger product.
To this end, the apparatus of the present invention was developed and which comprises as the foaming chamber an inverted conical chamber. The foamable composition is introduced into the apex of the inverted cone chamber and allowed to foam. As the foaming proceeds, the composition is moved vertically up the cone towards the base of the cone, which is vertically above the apex, and from thence to a forming apparatus which in one embodiment is a tunnel or nozzle which imparts the final desired shape to the foaming composition.
With the foregoing arrangement, the molecules of the composition show a greater degree of bi-axial orientation which is believed to impart substantially greater structural integrity and strength to the resulting product than has previously been the case where foaming has occurred substantially along a single axis while expansion along axes transverse to the single axis has been inhibited.
Further advantages of the apparatus of the present invention will become apparent as consideration is given to the following detailed description taken in conjunction with the accompanying drawings, in which: